Encapsulation of readily oxidizable components

ABSTRACT

A stabilized emulsion is mixed with plasticizable matrix material to produce shelf stable, controlled release, discrete, solid particles or pellets which contain an encapsulated and/or embedded component, such as a readily oxidizable component, such as omega-3 fatty acids. An oil encapsulant component which contains an active, sensitive encapsulant, dissolved and/or dispersed in an oil is admixed with an aqueous component and a film-forming component, such as a protein, to form an emulsion. The emulsion is admixed with a matrix material for obtaining a formable mixture or dough. An acidic antioxidant for prevention of oxidation of the active, sensitive encapsulant, and a plasticizer which solubilizes the acidic antioxidant are included in the matrix material which encapsulates film-coated oil droplets containing the readily oxidizable component. The plasticizer, such as glycerol, provides mobility for the acidic antioxidant within the matrix material of the pellets for reaction with any ambient oxygen and malodorous amines.

This application is a divisional application of application Ser. No.11/500,545, filed Aug. 8, 2006, now U.S. Pat. No. 7,803,414 which is acontinuation-in-part application of application Ser. No. 11/263,360filed Oct. 31, 2005, now U.S. Pat. No. 7,803,413 and is also adivisional application of application Ser. No. 11/263,360 filed Oct. 31,2005, the disclosures of which are herein incorporated by reference intheir entireties.

FIELD OF THE INVENTION

The present invention relates to a continuous process for producingshelf-stable, discrete, solid particles which contain an encapsulatedand/or embedded component such as a heat sensitive or readily oxidizablepharmaceutically, biologically, or nutritionally active polyunsaturatedfatty acid, such as omega-3 fatty acids.

BACKGROUND OF THE INVENTION

In encapsulating a component in a matrix, the matrix material isgenerally heated to a sufficiently high temperature to provide aplasticized mass which facilitates embedding or coating of thecomponent. Upon cooling, the matrix material hardens or becomessolidified and protects the encapsulant from undesirable or prematurereaction. Grinding of a solidified or glassy product to obtain a desiredparticle size for incorporation in foods or beverages generally resultsin the formation of irregularly-shaped pieces and rough surfaces.Irregularly shaped pieces and creviced surfaces tend to result innon-uniform encapsulant release, increased diffusion of liquidencapsulants, and increased penetration of oxygen and water which maydeleteriously affect sensitive encapsulants, such as readily oxidizablecomponents. Incorporation of a water soluble antioxidant, such as anacidic antioxidant into a dry matrix material may not be effective forpreventing oxidation because of the substantial absence of a fluidreaction medium for the antioxidant or immobilization of theantioxidant. Increasing the water content of the matrix material toimprove antioxidant mobilization may result in a water activity which isnot shelf stable, may adversely affect a desirable crispy texture, ormay adversely affect the release properties of the matrix.

Prophylactic and therapeutic benefits of omega-3 fatty acids and theirrole as anti-inflammatory agents are well-proven. Recent clinicalstudies have further suggested that consumption of sufficient amounts ofthese polyunsaturated fatty acids may be adequate for interventiontreatment for animals and humans suffering from rheumatoid arthritis.Dietary sources of omega-3 fatty acids can be found mainly in foods frommarine sources such as algae and fish. In most populations, however, thenutritional benefits of polyunsaturated fatty acid (PUFA) compoundscannot be realized due to the low consumption of fish and edible algae.With the U.S. Food and Drug Administration=s current allowance forhealth claims relating to intake of omega-3 fatty acids for protectionfrom heart disease, there is an increased interest in fortifying foodproducts with these components. One main problem that hinders theincorporation of omega-3 PUFA oils into processed foods is the oil=shigh degree of unsaturation, its susceptibility to oxidation and thesubsequent deteriorative effects on flavor and aroma of the oil.

The stabilization of omega-3 fatty acid compounds is disclosed in U.S.Pat. No. 5,567,730 to Miyashita et al. One or more of the compounds oran oil or fat containing the compounds is dispersed in an aqueoussolution optionally using a surface active agent or an emulsifyingagent, such as Tween 20, a sucrose fatty ester, a sorbitan fatty ester,lecithin and a monoglyceride. A water soluble or oil solubleanti-oxidizing agent or a clathrate inclusion compound such ascyclodextrin can be used together with the surface active agent oremulsifying agent. When no surface active agent or emulsifying agent isused, the amount of the omega-3 fatty acid to added to the aqueoussystem to allow the stabilization is 0.0001-0.3 (w/v) %. When the agentis employed the amount of the omega-3 fatty acid to be added to theaqueous system to allow the stabilization is still only 0.0001-7 (w/v)%. Production of shelf-stable, discrete, solid particles which containomega-3 fatty acids or fish oils is not disclosed.

International patent publication no. WO 95/26752 (published Oct. 12,1995) discloses the production of a food product for the enteric supplyof a fatty acid, a fatty acid containing substance, an amino acid, or anamino acid containing substance by at least partially complexing thefatty acid or amino acid in the amylose helix of starch to mask theacid. The product may contain one or more flavors and colors, fatsoluble substances, anti-oxidants, or pharmacologically effectivesubstances. The components may be first dry mixed and subsequently fedinto an extruder where they are substantially mixed and subsequentlyheated above the gelatinization temperature of the starch to obtain anelasticized mass which is extruded and formed into pellets. However,heat-sensitive components would be destroyed during the heating step.

U.S. Pat. No. 4,895,725 to Kantor et al discloses the microencapsulationof oil-based bioactive materials, such as fish oil which containpolyunsaturated fatty acids. The microcapsules are prepared from anemulsion of fish oil and an enteric coating suspended in a basicsolution, preferably a 25% suspension of ethyl cellulose in ammoniumhydroxide. The emulsion is atomized into an acidic solution using aninert gas such as nitrogen or argon. The resulting microcapsules arefiltered out of the acidic solution, washed with water and a surfactantand dried. The conditions under which the emulsion is atomizeddetermines the particle size, which can range from about 0.1 to 500microns, preferably between about 0.5 to 100 microns. However, theenteric coating, such as ethylcellulose is not solubilized and theresulting suspension requires atomization into an acidic aqueoussolution to produce microcapsules. Filtering and several washing stepsare needed to recover the microcapsules. Control of oil droplet sizes byhomogenization so as to avoid coalescence and obtain a substantiallyuniform oil droplet size is not disclosed. Protection or prevention ofthe microcapsules from cracking, or rupturing is not taught. Also,prevention or inhibition of diffusion of the oil through the capsulewall to the microcapsule surface, and penetration of oxygen through thecapsule wall into the oil are not disclosed.

The production of expanded products is disclosed in European patentpublication nos. EP 0465364 A1 (published Jan. 8, 1992) and EP 0462012A2 (published Dec. 18, 1991), U.S. Pat. No. 3,962,416 to Katzen and U.S.Pat. No. 3,786,123 to Katzen. The two European patent publicationsdisclose the production of an anti-obesity food and a method for makingit by extrusion of starches with fatty acids into an expanded producthaving densities between 0.1 and 0.3 g/cm³. U.S. Pat. No. 3,962,416 toKatzen discloses an expanded product which contains at least onenutrient and one gelatinized starch.

U.S. Pat. No. 3,786,123 to Katzen discloses a method for producingencapsulated nutrients using extrusion temperatures of between 250° F.and 400° F. and extrusion pressures of between 200 psi to 2500 psi. Ahigh protein encapsulating agent containing up to 40% starch may beused. The starch is gelatinized and extruded into an expanded product.

However, in producing a product having controlled release or delayedrelease, excessive expansion or puffing may result in too rapid releaseproperties or may undesirably expose an encapsulant to destructivereactions. For example, in the case of an edible composition fordelivering encapsulated pharmaceutically or nutritionally activecomponents or a non-edible agricultural product for delivering biocidesor herbicides, it is desirable that the products have a substantiallyspherical shape and a high density. Such products exhibit asubstantially low ratio between surface area and volume and thusminimize or prevent surface related destructive reactions that occurupon exposure to air or oxygen and light. The spherical shapes and highdensities also minimize the specific surface which would be available toexpose embedded material which is not encapsulated. Furthermore, foredible products for delivering pharmaceutically or nutritionally activecomponents, it is desirable that the products are capable of beingconsumed or swallowed without chewing or substantially no chewing.Avoiding the need for mastication, further assures that the productsreach the digestive tract without substantial enzymatic hydrolysis inthe mouth. Furthermore, it helps to control or reduce dissolution of theproduct in gastric juice and to control the release of the embedded orencapsulated components in the stomach and/or in the intestine.

International patent publication no. WO 92/00130 (published Jan. 9,1992) discloses a continuous process for obtaining an encapsulated,biologically active product in a starchy matrix. A biologically activeagent and starch are mixed before extrusion and extruded as a blend,with the encapsulant or biologically active agent being heated togetherwith the starch. Alternatively, a core material to be encapsulated maybe added and blended with an aqueous dispersion of starch after thestarch and water have been subjected to an elevated temperaturesufficient to gelatinize the starch. The extrusion process, it isdisclosed, exposes the mix to high shear mechanical action at atemperature above the gelatinization temperature of the starch. The useof extrusion barrel temperatures of between about 58° C. and 98° C. aredisclosed. While these barrel temperatures may be above thegelatinization temperature of starch, the extruder utilized has barrelsections that are only three l/d long. The screw speeds utilized,between 400 rpm and 200 rpm, result in a very short residence time ofthe blend inside the extruder and barely allow heating up of the starchwater mix. As a result, the temperatures obtained are generally too lowto obtain substantial gelatinization of native starches. Additionally,the barrel temperatures used are particularly too low for substantialgelatinization of high amylose starch which generally gelatinizes attemperatures substantially above 100° C., for example at 125° C. The useof extrusion barrel temperatures which are not sufficiently high tosubstantially or completely gelatinize the starch may not form asufficiently continuous, plasticized and homogeneous matrix foreffective embedding or encapsulation.

In addition, the use of relatively low extrusion temperatures, highspeed mixing, and a high viscosity starch composition generally requiresa high mechanical energy input. High shear is directly related to highspecific mechanical energy, which in turn increases the moleculardestructurization and dextrinization of starch. Breakdown of the starchmolecules, and in particular the amylopectin, increases the solubilityof the extruded starch composition in aqueous systems as described in P.Colonna, et al., “Extrusion Cooking of Starch & Starchy Products,”Extrusion Cooking, C. Mercier, et al. pp. 247-319, AACC, St. Paul, Minn.(1989) and F. Meuser, et al, “A Systems Analytical Approach ToExtrusion,” Food Extrusion Science & Technology, ed. J. Kokini, DekkerPubl., pp. 619-630 (1992). Increased solubility of the extruded starchin aqueous systems decreases the stability of the product againstmoisture and subsequently diminishes or shortens the protection andcontrolled release of the embedded or encapsulated substances. Inaddition, subjecting the encapsulant to the same high shear and hightemperature conditions to which the starch is subjected may adverselyaffect the encapsulant by at least partially destroying it ordecomposing it into unknown solid or volatile substances.

Pregelatinized starch is used in numerous applications in the foodindustry as a swelling agent and for accelerated and extended waterabsorption in foods such as soups, sauces, instant puddings, baby food,and thickening agents. However, it has been found that the use ofpregelatinized starch or the use of starch as the only matrix materialduring extrusion cooking generally results in a matrix which releasesthe encapsulant too quickly. It has been found that the penetration ofwater into a pure starch matrix causes early release of the encapsulantinto the environment. Generally the time to release 100% of theencapsulant is too short to provide a desirable time-release orcontrolled-release which is effective for delivering the encapsulant ata desired location or time.

U.S. Pat. No. 5,183,690 to Carr, et al. discloses a continuous processfor imparting predetermined release properties to an encapsulatedbiologically active agent in a matrix of starchy material. The starchymaterial, an active agent, and water are continuously blended in aningredient stream wherein the starchy material is at a solidsconcentration of at least 40%. The ingredients stream is continuouslyextruded as an extrudate and the extrudate is continuously recovered.The conditions of blending, extruding, and recovering are preselected toyield the predetermined release properties. The temperature is elevatedto at least about 65° C. to effect gelatinization of starch and assurean essentially molecular dispersion of the starch in the water.Alternatively, the core material to be encapsulated is added and blendedwith the aqueous dispersion of starch after the starch and water hasbeen subjected to an elevated temperature sufficient to gelatinize thestarch. In this embodiment the aqueous starch stream containinggelatinized starch may be lowered to a temperature as low as about 25°C. before the core material to be encapsulated is added and subjected tohigh-shear mechanical action. Under such low temperature conditions ofadmixture it is disclosed, the activity of sensitive biologicalmaterial, such as bacteria and viruses, is preserved and loss ofvolatile organic materials is minimized. The rate of swelling of theproducts in water and the rate of release of active agents arecontrolled by altering the amount of water present in thestarch-agent-water blend during processing. As the amount of water isdecreased, both the swelling rate and the release rate increase. Therate of swelling of the products in water and the rate of release ofactive agent are also controlled by passage of the extrudate containingstarch-agent-water through an exit die of various dimensions. As theexit die is reduced in size, both the rate and extent of swellingincrease and the rate of release of agent increases.

U.S. Pat. No. 6,190,591 and International Publication No. WO 98/18610,published on May 7, 1998, both to Bernhard H. van Lengerich, thedisclosures of which are herein incorporated by reference in theirentireties, disclose a controlled release particulate composition whichcontains a hydrophobic component for controlling the release of anencapsulated and/or embedded active component from a plasticized matrix.High water binding capacity agents may also be used to delay or controlthe release of the encapsulant from the matrix. A high amount ofplasticizer is employed to facilitate plasticization of the matrixmaterial at low shear and is then reduced prior to adding theencapsulant to facilitate subsequent forming and to reduce postextrusion drying. Liquid active components or solutions, dispersions,emulsions or suspensions may be injected into the plasticized matrixmaterial. The controlled release or delayed release composition may beproduced without substantial expansion of the matrix material to therebyavoid production of a low density product which prematurely or toorapidly releases the encapsulant or the embedded component.

Copending U.S. application Ser. No. 09/233,443, filed Jan. 20, 1999 inthe name of Bernhard H. Van Lengerich, International Publication No. WO00/21504 published on Apr. 20, 2000, U.S. Pat. No. 6,500,463 to VanLengerich, and International Publication No. WO 01/25414 published onApr. 12, 2001, the disclosures of which are herein incorporated byreference in their entireties, disclose a continuous process forproducing shelf-stable, controlled release, discrete, solid particlesfrom a liquid encapsulant component which contains a sensitiveencapsulant, such as a heat sensitive or readily oxidizablepharmaceutically, biologically, or nutritionally active component, suchas essential and/or highly unsaturated fatty acids. A liquid encapsulantcomponent which contains an active, sensitive encapsulant, such as alive microorganism or an enzyme dissolved or dispersed in a liquidplasticizer is admixed with a plasticizable matrix material. The matrixmaterial is plasticizable by the liquid plasticizer and theencapsulation of the active encapsulant is accomplished at a lowtemperature and under low shear conditions. The active component isencapsulated and/or embedded in the plasticizable matrix component ormaterial in a continuous process to produce discrete, solid particles.The encapsulants may be suspensions of microorganisms in water, andsuspensions or dispersions or emulsions or solutions of vitamins,enzymes, minerals or trace elements in water or other liquids. Theliquid content of the liquid encapsulant component providessubstantially all or completely all of the liquid plasticizer needed toplasticize the matrix component to obtain a formable, extrudable,cuttable, mixture or dough. Removal of liquid plasticizer prior toextrusion is not needed to adjust the viscosity of the mixture forformability.

U.S. Pat. No. 5,064,669 to Tan et al relates to the production ofcontrolled release flavors for microwaveable foods. Controlled-release,flowable flavoring powders are produced by: a) heating ahigh-melting-point encapsulating or enrobing material (fat and/or waxand one or more emulsifiers) to melt the starting material; b) mixingone or more water-containing flavor compositions with a textureconditioning agent; c) mixing the flavor compositions and texturecontaining agent with the molten fat or wax to obtain a homogeneousmixture in the form of an emulsion; and d) chilling the flavorcomposition-containing mixture to provide discrete particles of solidencapsulated flavoring agent.

U.S. Pat. No. 5,106,639 to Lee et al discloses a process for preparingfatty fodder additives by mixing an emulsifier, a carrier, and a fatmaterial containing omega-3 fatty acids to produce an emulsion,homogenizing the emulsion, and drying the emulsion to produce a powderedfat. The emulsion may also contain water and whey. The carrier may besoybean protein, skim milk solids, starch, pectin, gelatin, casein,collagen, and egg protein. After spray drying or fluidized bed drying,the particulate fat product generally has a particle size ranging fromabout 0.1 to about 1.0 millimeters. An enteric coating comprising acellulosic material may be applied to the powdered fat.

U.S. Patent Application Publication No. US 2004/0017017 A1, publishedJan. 29, 2004 to Van Lengerich et al, the disclosure of which is hereinincorporated by reference in its entirety, discloses production of astabilized oil-in-water emulsion which contains a readily oxidizablecomponent or a heat sensitive component. An antioxidant for preventionof oxidation of the active, sensitive encapsulant, and a film-softeningcomponent or plasticizer for the film-forming component may be includedin the emulsion. The emulsion is stabilized by subjecting it tohomogenization. Shelf stable, controlled release, discrete, solidparticles or pellets which contain an encapsulated and/or embeddedreadily oxidizable component or a heat sensitive component are producedby first reducing the water content of the stabilized emulsion.Reduction of the water content causes the film-forming component to forma film around the oil droplets and encapsulate the encapsulant. Thewater content of the homogenized emulsion may be reduced by spray-dryingto produce a powder. In other embodiments, after homogenization, thewater content of the emulsion may be reduced by admixing the emulsionwith at least one matrix material to thereby encapsulate the film-coatedoil droplets within the matrix material. After the water content of theemulsion is reduced, a protective coating is applied on the film-coatedoil droplets to obtain pellets. The protective coating helps to preventdiffusion of the oil component to the surface of the pellets, and helpsto inhibit penetration of atmospheric oxygen into the encapsulated oilcomponent. The protective coating also fills in or seals any crevices,cracks, irregularities, or pores in the underlying substrate and helpsto provide a more smooth surfaced, uniform pellet or cluster. Afterapplication of the protective coating, the pellets may be dried toobtain the final encapsulated product.

Inclusion of an antioxidant in the oil phase or oil droplets generallymakes it mobile for interacting with any ambient oxygen invading theencapsulated readily oxidizable component. However, addition of anacidic antioxidant into the aqueous phase of an emulsion may lead to anincreased emulsion viscosity due to interactions with certain proteins(protein emulsifiers) which could impede attainment of small oil dropletsizes. Also, it would also be beneficial to include an antioxidant inthe matrix material so as to help prevent the oxygen from even reachingthe readily oxidizable component in the oil droplets. However, whenincorporating an acidic antioxidant into the matrix material, it hasbeen found that upon drying the pellets to a shelf stable wateractivity, the acidic antioxidant tends to crystallize and becomeimmobilized. Immobilization of the acidic antioxidant inhibits itsinteraction with invading ambient oxygen.

The present invention provides a process for producing discrete,particulate, shelf-stable encapsulated sensitive components, such asheat-sensitive components or readily oxidizable components, such asomega-3 fatty acids. Exposure of the sensitive components to atmosphericoxygen may be substantially prevented without the need for a protectivesurface coating on the particulates. The process avoids the need toincorporate substantial amounts of acidic antioxidants in the aqueouscomponent of the emulsion which tend to react with certain proteinaceousfilm-forming components which could impede attainment of small oildroplet sizes. In accordance with the present invention, an acidicantioxidant may be incorporated in a matrix material without loss ofmobility, for example by use of a non-aqueous plasticizer to enhanceantioxidant efficiency, for interaction with any invading ambientoxygen. The processes of the present invention may be used for thecontinuous production of an edible composition for deliveringpharmaceutically or nutritionally active components, such as omega-3fatty acids. The particulates containing encapsulated oils withpolyunsaturated fatty acids from, for example, fish, algae, flax orother seeds, and food products containing the particulates do notexhibit rancid odors or tastes for extended periods of time, for examplefor at least about six months.

SUMMARY OF THE INVENTION

A readily oxidizable component, such as a polyunsaturated fatty acid, isencapsulated by forming an oil-in-water emulsion with a film-formingcomponent, such as a protein or a modified starch, for coating oildroplets of the oil phase. The readily oxidizable component is presentin the oil phase and is protected from oxidation by a film formed fromthe film-forming component. The oil-in-water emulsion is admixed with atleast one matrix material, a liquid plasticizer such as water orglycerol, for plasticizing the matrix material, and an acidicantioxidant for preventing oxidation of the readily oxidizablecomponent. The acidic antioxidant is solubilized in the liquidplasticizer. Separation of the acidic antioxidant from a proteinfilm-forming component, such as a caseinate, during emulsion formationand homogenization, avoids possible deleterious interaction between theprotein and the acidic antioxidant.

A formable mixture or dough is obtained where the at least one matrixmaterial contains the acidic antioxidant and encapsulates film-coatedoil droplets of the oil-in water emulsion. The dough is formed intopieces or pellets which may be dried to a shelf stable water activity ofless than or equal to about 0.7.

The plasticizer provides mobility for the acidic antioxidant within thematrix material in the dried pieces so that the antioxidant can reactwith any ambient oxygen entering the pieces before the oxygen can reachand react with the readily oxidizable component. The acidic antioxidantneutralizes and helps in the prevention of malodorous basic compounds,such as amines of fish oil, from escaping out of the pellets.

DETAILED DESCRIPTION OF THE INVENTION

A stabilized emulsion is employed to produce shelf stable, controlledrelease, discrete, solid particles or pellets which contain anencapsulated and/or embedded component, such as a readily oxidizablecomponent containing a polyunsaturated fatty acid. An oil encapsulantcomponent which contains an active, sensitive encapsulant dissolvedand/or dispersed in an oil is admixed with an aqueous component and afilm-forming component to form an emulsion. The emulsion is stabilizedby subjecting it to homogenization. The stabilized emulsion is admixedwith at least one plasticizable matrix material and a plasticizer forplasticizing the at least one matrix material to encapsulate oildroplets which are coated with the film forming component. An acidicantioxidant for prevention of oxidation of the active, sensitiveencapsulant is dispersed throughout the at least one matrix material.The plasticizer provides mobility to the antioxidant throughout theplasticized matrix material. The acidic antioxidant neutralizes andhelps to prevent escape of malodorous basic compounds, such as aminesfrom the pellets.

In embodiments, the antioxidant may be added to the at least one matrixmaterial, to a plasticizer that is mixed with the at least one matrixmaterial, or to a plasticizer during emulsion preparation and formation.Exemplary acidic antioxidants or proton-donating antioxidants which maybe employed in effective amounts in the matrix material are organicacids such as L-cysteine, acetic acid, tartaric acid, lactic acid, malicacid, citric acid, fumaric acid, propionic acid, tannic acid, ascorbicacid, iso-ascorbic acid, and erythorbic acid, tocopherol, catechin,salts thereof, isomers thereof, derivatives thereof, and mixturesthereof. Exemplary salts which may be employed are alkaline earth metaland alkali metal salts, such as calcium, potassium, and sodium salts ofascorbic acid, erythorbic acid, and L-cysteine, and phenolic salts.Exemplary derivatives include acid anhydrates, esters, amides, andlipophilic acids. The preferred acidic antioxidants for use in thematrix material are organic acids such as citric acid, ascorbic acid anderythorbic acid, most preferably erythorbic acid or ascorbic acid.

The amount of the acidic antioxidant may be from about 1% by weight toabout 40% by weight, preferably from about 2% by weight to about 30% byweight, for example from about 3% by weight to about 20% by weight, morepreferably from about 10% by weight to about 30% by weight, mostpreferably from about 15% by weight to about 25% by weight, based uponthe weight of the oil component or the weight of the pellet. Inembodiments of the invention, the amount of acidic antioxidant may be upto about 5% by weight or 6% by weight, or up to about 18% by weight, forexample from about 0.5% by weight to about 6% by weight, for examplefrom about 0.5% by weight to about 4% by weight, based upon the weightof the pellet.

The plasticizer or combination of plasticizers for dispersing andmobilizing the acidic antioxidant throughout the matrix material maycontain at least one liquid which solubilizes the acidic antioxidant andis retained in the pellet after drying in a sufficient amount to preventsubstantial crystallization of the acidic antioxidant, and providemobility to the acidic antioxidant in the dried pellet. It is assumedthat the mobility provided should be such so that the acidic antioxidantcan react with any ambient oxygen which enters the pellet interior ormatrix material to prevent the oxygen from penetrating into thefilm-coated oil droplets. Also, the plasticizer should keep the acidantioxidant solubilized and prevent substantial crystallization in thedried pellet. The mobility should enable the acidic antioxidant todonate protons to terminate any radicals from the fatty acids and/orreact with any malodorous amines given off by fish oils. Exemplary ofmobilizing plasticizers which may be employed with the acidicantioxidant are water, polyols or glycols such as glycerol, propyleneglycol, and polyethylene glycol, sugar alcohols such as sorbitol,monosaccharides, and di-saccharides such as fructose, and dextrose, andmixtures thereof. Glycerol is the preferred mobilizing plasticizer orsoftener for admixing with the acidic antioxidant.

While water may be employed to plasticize the matrix material as well asto solubilize the acidic antioxidant, drying of the pellets to achieve ashelf stable water activity of less than about 0.7 generally results insubstantial crystallization and immobilization of the acidic antioxidantin the pellet. Accordingly, water or aqueous solutions which enableforming a dough, such as fruit juice, may be employed as a plasticizerin the matrix to facilitate mixing and initial dispersing andhomogenization of the antioxidant. However, a less volatile, liquidplasticizer or softener such as a polyol should also be employed toachieve shelf stability and acidic antioxidant mobility in the finalpellet. Water or aqueous solutions employed as a plasticizer for thematrix material may be admixed with the non-aqueous plasticizer orsoftener or it may be separately added to the matrix material. Waterwhich is used to form the oil-in-water emulsion also serves toplasticize the plasticizable portion of the matrix material.

The amount of the non-aqueous mobilizing plasticizer or softener, suchas glycerol, should be sufficient to solubilize the antioxidant.Exemplary amounts of the non-aqueous mobilizing plasticizer or softenermay range from about 1% by weight to about 50% by weight, preferablyabout 1% by weight to about 25% by weight, more preferably from about10% by weight to about 20% by weight, based upon the weight of thepellet.

The pellets are produced by first reducing the water content of thestabilized emulsion so that the film-forming component forms a filmaround the oil droplets and encapsulates the encapsulant. Afterhomogenization, the water content of the emulsion may be reduced byadmixing the emulsion with at least one matrix material to therebyencapsulate the film-coated oil droplets within the matrix material. Inembodiments of the invention, the pH of the pellets may range from about2.5 to about 8.

Preparation of the Stabilized Oil-In-Water Emulsion

Improved dispersion and encapsulation of active, sensitive encapsulantmaterials in discrete shelf-stable particles is obtained bypre-emulsification of the encapsulant. The encapsulant is incorporatedinto or forms the oil phase of an oil-in-water emulsion. Theoil-in-water emulsion containing the encapsulant is admixed with atleast one matrix material, such as a plasticizable matrix material, toencapsulate the encapsulant within the matrix material. Using matrixmaterials which are plasticizable by the emulsion or the aqueouscomponent of the emulsion, results in encapsulation of the encapsulantwithin a plasticized matrix material. The encapsulant or sensitive,active component may be a solid or liquid. Solid encapsulants aredispersed in an oil prior to emulsification with water or an aqueousliquid. If the encapsulant itself is an oil, it may be directlyemulsified with the water or aqueous liquid.

In embodiments of the present invention, the aqueous component, such aswater or an acidic aqueous solution, such as a 0.2N acetic acid inwater, may be admixed with the film-forming component, such as aprotein, to obtain an aqueous solution. The film-forming component helpsto stabilize the emulsion, retain oil droplet size, inhibit diffusion ofthe oil component and encapsulant to the particulate or pellet surface,and to inhibit contact of rancidity-causing oxygen with the oilcomponent.

The aqueous solution, such as an aqueous protein solution, may have afilm-forming component content, or protein content, of from about 1% byweight to about 50% by weight, preferably from about 5% by weight toabout 25% by weight, most preferably from about 8% by weight to about15% by weight, based upon the total weight of the aqueous component,such as water, and the film-forming component, such as protein.

In embodiments of the invention, glycerol may replace water in theoil-in-water emulsion to form oil-in-glycerol emulsions. Preferably upto about 100% by weight of water, for example up to about 60% by weightof the water, in the oil-in-water emulsion may be replaced withglycerol. Such an emulsion allows for higher oil loads in the finalpellet or product and also lowers extrudate moisture, thereby loweringdrying requirements and air exposure. Accordingly, oxidative stabilitymay be enhanced. In embodiments, the emulsion may comprise about 50% byweight of oil, about 5% by weight of a film-forming component such assodium caseinate, about 27% by weight of glycerol, and about 18% byweight of water, based upon the weight of the emulsion.

In embodiments of the invention, the film-forming component is watersoluble and may comprise a hydrophobic or oleophilic portion, such as afilm-forming protein, so that it may concentrate at the oil and waterinterface. Film-forming components which may be employed include, butare not limited to, proteins; carbohydrates; hydrocolloids, such asalginates, carrageenans, and gums; starches, such as modified starch andstarch derivatives; or mixtures thereof. Proteins are the preferredfilm-forming components for use in the emulsification. Exemplaryproteins which may be employed are one or more vegetable proteins, dairyproteins, animal proteins, or protein concentrates, such as proteinsstemming from milk, whey, corn, wheat, soy, or other vegetable or animalsources. Preferred proteins for use in the present invention are dairyproteins such as caseinates and whey protein isolates, and wheat proteinisolates, such as gluten. Caseinates, such as sodium caseinate,potassium caseinate, calcium caseinate, and ammonium caseinate are mostpreferred proteins for use in the present invention.

The caseinates are readily soluble proteins, and provide lower viscosityaqueous phases compared to viscosities obtained with other proteins,such as whey protein isolates. The lower viscosity facilitatesemulsification and homogenization with the oil phase, and the attainmentof small oil droplet sizes, and unexpectedly superior microencapsulationefficiency.

Microencapsulation efficiency (ME) may be calculated as follows:ME=[(Total oil−Free oil)/Total oil]×100[%]

The quantitative determination of the total oil content of the samplesmay be accomplished by acid hydrolysis followed by extraction accordingto the WEIBULL-STOLDT method. The free, accessible or non-encapsulatedoil in the extrusion pellets may be determined according to a modifiedmethod after SANKARIKUTTY et al., “Studies on Microencapsulation ofCardamom Oil by Spray Drying Technique”, Journal of Food Science andTechnology, vol. 6, pp. 352-356 (1988), HEINZELMANN et al.,“Microencapsulation of Fish Oil by Freeze-Drying Techniques andInfluence of Process Parameters on Oxidative Stability During Storage”,European Food Research and Technology, vol. 211, pp. 234-239 (2000),McNAMEE et al., “Emulsification and Microencapsulation Properties of GumArabic”, Journal of Agricultural and Food Chemistry, vol. 46, pp.4551-4555 (1998), McNAMEE et al., “Effect of Partial Replacement of GumArabic with Carbohydrates on its Microencapsulation Properties”, Journalof Agricultural and Food Chemistry, vol. 49, pp. 3385-3388 (2001), andHOGAN et al., “Microencapsulation Properties of Sodium Caseinate”,Journal of Agricultural and Food Chemistry, vol. 49, pp. 1934-1938(2001). A sample with a total oil content of approximately 1 g (e.g. 7 gof extrusion pellets with an oil content of approximately 15%) may betransferred in 100 ml petroleum ether (boiling point: 60-80° C.) andstirred with a magnetic stirrer for exactly 15 minutes at ambienttemperature. After the following filtration (Schleicher & Schuell 595)the filtrate may be transferred into an extraction apparatus afterSOXHLETT and the solvent may be evaporated at 80° C. The received oilresidue may be dried in a drying oven (Heraeus 6060, Kendro LaboratoryProducts, Hanau, Germany) at 105° C. to constant (or minimum) weight andquantified gravimetrically (approximately 1 hour). Under the conditionsof the pre-described method the free oil is completely removed from thepellets already after 15 minutes. An increase of the agitation time upto 60 minutes did not entail significant changes. Compared with othersolvents, i.e., alcohols, ethers, water and/or mixtures thereof, the useof petroleum ether results in the highest content of free oil. Inembodiments of the present invention, the microencapsulation efficiencymay be greater than about 85%, preferably greater than about 90%.

The protein may be at least substantially or completely hydrated anddenatured prior to admixing with the oil component to avoid clumping andto facilitate subsequent pumping through the homogenizer. Hydration canbe accomplished by preparing the solution either immediately before useor up to a day before use and storing it under refrigerated conditionsto permit any foam or froth resulting from the mixing to settle.

The protein, such as whey protein isolate (WPI), can be kept in eitherthe native form or can be denatured prior to emulsification with thefish oil. Denaturation can be achieved by heating the dispersed WPIsolution to about 80° C.-90° C. and holding for 30 minutes. DenaturedWPI solutions appear to form better films than native WPI solutions andmay add to the stability of the final encapsulated oil. In either case,the whey protein isolate can serve as an emulsifier in the finalemulsion with oil. Again, it is desirable to allow the WPI solutions(native or denatured) to fully hydrate and cool under refrigeratedconditions, for example at about 40° C., prior to use.

In embodiments of the present invention, the emulsion may be made byadmixing one or more optional ingredients with the aqueous film-formingcomponent solution, such as the aqueous protein solution, using a highshear mixer such as an ULTRA-TURRAX ROTOSOLVER high shear mixer or othermixer with adequate shear. Such optional ingredients include afilm-softening component or plasticizer, a non-acidic antioxidant, anacidic antioxidant, a flavor, and an emulsifier in amounts which do notadversely affect viscosity for emulsification and homogenization and theachievement of small oil droplet sizes and a stable emulsion. When areadily oxidizable encapsulant such as omega-3 fatty acids is to beencapsulated, mixing of the optional ingredients with the emulsion ispreferably conducted in an atmosphere which is at least substantiallyfree of oxygen, such as under a nitrogen blanket or inert gas blanket.Preferably to prevent and/or minimize oxygen exposure, a nitrogenblanket can be applied in subsequent locations when the fish oil isdirectly exposed to the atmosphere.

A film-softening component or plasticizer for reducing brittleness andpreventing cracking of the film formed from the film-forming componentwhich may be optionally added in the emulsion step includemonosaccharides and disaccharides, such as sucrose and fructose, andpolyols such as glycerol, and polyethylene glycol. The amount of thefilm-softening component or plasticizer may be from about 1% by weightto about 75% by weight, preferably from about 15% by weight to about 50%by weight, based upon the weight of the film-forming component.

For the encapsulation of readily oxidizable components such aspolyunsaturated fatty acids, such as omega-3 fatty acids in oils fromfish, algae, flax, seeds, microorganisms or other sources, the emulsionis preferably prepared in an atmosphere substantially free of oxygen,such as a nitrogen blanket, and a non-acidic antioxidant or an acidicantioxidant may optionally be added in the emulsion step to the aqueousphase or to the oil phase. Exemplary antioxidants which may be employedare L-cysteine and its salts, ascorbic acid and salts thereof,erythorbic acid and salts thereof, tocopherol, catechin, TBHQ,phenolics, natural antioxidants such as grape seed extract which containantioxidant phenolics, and nut fibers, such as almond fiber, andmixtures thereof. TBHQ may or may not be present in the oil employed asa raw material, but even if present, may be added additionally in theoil prior to emulsification. For example, TBHQ may be added to the oilin an amount of about 10 ppm to about 1200 ppm, more preferably fromabout 600 ppm to about 1000 ppm, based upon the weight of the oilcomponent. Mixed tocopherols may be added to the oil at concentrationsof from about 10 ppm to about 1000 ppm. In embodiments of the invention,the amount of the optional antioxidant employed in the emulsion step mayrange from about 10 ppm by weight to about 10,000 ppm by weight, forexample from about 50 ppm by weight to about 1,000 ppm by weight, orabout 100 ppm by weight, based upon the weight of the oil component.

An acidic antioxidant, a non-acidic antioxidant, or a film softeningcomponent or plasticizer may optionally be employed in the emulsion. Inembodiments, the optional antioxidant employed in the emulsion may bethe same as or different from any antioxidant that may be employed inthe matrix. In embodiments of the invention, it is preferable to onlyemploy an acidic antioxidant and a plasticizer for mobilization of theacidic antioxidant in the matrix material. The mobilizing plasticizerand the acidic antioxidant in the matrix material serves to preventoxidation of the oxidizable component in the film-coated oil droplets.Also, the mobilized plasticizer migrates to the film forming componentand helps to reduce its brittleness.

In embodiments, the acidic antioxidant may be added to the matrixmaterial to avoid possible deleterious interaction between the proteinand the acidic antioxidant. In other embodiments of the invention, thisdeleterious interaction may be overcome by adding the protein (such assodium caseinate) to an already-acidified medium in which the pH of themedium is above or below the protein isoelectric point (e.g., for sodiumcaseinate about 4.4 to about 4.6).

Any compatible flavor may optionally be added to the oil phase to maskoff-flavors and off-odors in the oil and to help chemically stabilizeoil. The flavor may be added at a level ranging from about 0.1% byweight to about 25% by weight, for example from about 1% to by weight toabout 25% by weight, preferably about 0.5% by weight to about 15% byweight, for example, from about 10% by weight to about 15% by weight,more preferably about 1% by weight to about 5% by weight, for example,from about 2% by weight to about 5% by weight, based upon the weight ofthe oil phase.

The oil phase and the aqueous phase components may be admixed in thehigh shear mixer, such as an ULTRA-TURRAX ROTOSOLVER for about 10minutes prior to high pressure multi-stage homogenization.

Once all of the ingredients for making the emulsion are admixed, theresulting emulsion or combination of ingredients may be run through ahomogenizer. The homogenizer total stage pressure may be from about 1psig to about 30,000 psig (about 7 kPa to about 206850 kPa), generallyat least about 2,000 psig (13790 kPa), preferably from about 4,000 psigto about 10,000 psig (about 27580 kPa to about 68950 kPa), mostpreferably from about 5,000 psig to about 7,000 psig (about 34475 kPa toabout 48265 kPa). The homogenization may be performed in one or morestages, using one or more passes through each stage. For example, twostages and three passes may be employed for the homogenization step. Inother embodiments, there may be as many as four discrete passes of theemulsion through the homogenizer, but more preferably there are two tothree passes. This process can produce a stable emulsion with dropletsizes less than about 2.1 microns (90 percentile), preferably less thanabout 1 micron (90 percentile). It is preferable to minimize heatexposure during homogenization as much as possible and to keep anitrogen blanket on all emulsion containers.

Pre-emulsifying of an encapsulant oil or an encapsulant-in-oil intowater or an aqueous liquid plasticizer may be achieved using amulti-step high pressure homogenizer either alone or in combination witha colloid mill to obtain minimum droplet size. High pressurehomogenization gives rise to small droplet sizes and may substantiallyimprove the distribution and dispersion, and bioavailability of active,sensitive encapsulants within a matrix material. Encapsulation of theemulsion within a matrix material can then be carried out undercontrolled, low pressure and low temperature conditions to preventcoalescence, oil separation, and extruder surging while giving a softformable mixture or dough comprising small droplets of an active,sensitive encapsulant dispersed throughout the dough or mixture. Thedough or mixture may be cut or shaped and dried to yield substantiallynon-expanded, discrete shelf-stable particles or pellets exhibiting animproved release profile of active encapsulant materials. An encapsulantmay optionally be included in the water phase of the emulsion. Anemulsifier may optionally be included to facilitate production orstabilization of the emulsion.

In high-pressure homogenization an oil encapsulant or encapsulant in-oilis mixed with water or an aqueous fluid to obtain small oil droplets.All, or at least substantially all, for example, at least about 90% ofthe oil droplets in the homogenized, stabilized emulsion and in thediscrete particulates, pellets, or encapsulated products of the presentinvention may have oil droplet sizes of less than about 50 microns indiameter, preferably less than about 10 microns in diameter, morepreferably less than about 2 microns in diameter, most preferably lessthan about 1 micron in diameter. In embodiments of the invention, theoil droplet diameters may be less than about 0.5 microns. The smallerthe droplets, the more stable is the emulsion which allows the formationof a dough without substantial coalescence of the droplets and oilseparation. Also, reduced coalescence and very fine dispersion mayincrease bioavailability of the encapsulant. Reduction in coalescenceincreases coating or encapsulation of the encapsulant by a continuousphase of plasticized matrix material, for example plasticized semolinaor mixtures of semolina and native starch. Use of a film-formingcomponent, which can also function like an emulsifier, for example avegetable or animal protein or protein concentrate can stabilize theemulsion by forming a thin film around the oil droplets duringemulsification processing. Non-film forming emulsifiers, monoglycerides,diglycerides, or triglycerides or mixtures thereof, or other moleculesthat are characterized as having a lipophilic and a hydrophilic part maybe employed to enhance stabilization of an oil encapsulant inside anouter aqueous phase. The smaller, substantially non-coalesced droplets,do not protrude from the matrix material, thereby reducing surfaceexposure of the oil coated encapsulant to air.

Encapsulants can either comprise an active oil component, or cancomprise a solid active, sensitive encapsulant component dispersed inoil. Readily oxidizable oil encapsulants may comprise, for example,castor oil, algae-based oil or oil derived from algae, flax oil or flaxseed oil, fish oil, seed oil, oil from microorganisms, or any other oilcontaining polyunsaturated fatty acids (PUFA) such as omega-3 fattyacids, such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA),docosapentaenoic acid, and linolenic acid, alpha-linolenic acid, omega-6fatty acids, fat soluble vitamins such as vitamins A, D, E, and K, gammalinoleic acid, alpha-linoleic acid, cod liver oil, flavorants, flavoroils, fragrances, active-ingredient containing extracts, e.g.chlorophyll or herbals, phytosterols, agricultural and pharmaceuticaland other bioactive components soluble in oil, and mixtures thereof. Inembodiments of the invention, the readily oxidizable oil encapsulant maybe any oil derived from any vegetable, animal, marine life, ormicroorganism which contains a substantial amount, for example at least5% by weight of a readily oxidizable component. Examples of oils whichmay contain a substantial amount of a readily oxidizable component areoils derived from soybeans and corn, sunflower oil, rapeseed oil, walnutoil, wheat germ oil, canola oil, hill oil, oil derived from yeast, blackcurrant seed oil, sea buckthorn oil, cranberry seed oil, and grape seedoil. Purified fish oils may, for example, have an omega-3 fatty acidcontent (DHA, EPA) of from about 25% by weight to about 49% by weight.Flax oil may have an omega-3 fatty acid content as high as about 71% byweight.

Solid encapsulants may include solid forms of pharmaceuticalcompositions or compounds, nutraceutical compositions or compounds,nutritional components, biologically active components, flavorants orflavorant compositions, fragrances or fragrance compositions,detergents, enzymes, pharmaceutically or nutritionally acceptable saltsthereof and mixtures thereof.

The encapsulant, for example a readily oxidizable oil, may be includedin an amount of from about 1% by weight to about 85% by weight, forexample from about 1% by weight to about 49% by weight, preferably fromabout 10% by weight to about 65% by weight, for example from about 10%by weight to about 45% by weight, most preferably from about 25% byweight to about 55% by weight, for example from about 25% by weight toabout 40% by weight, based upon the weight of the emulsion, or totalweight of the oil component and aqueous component. Edible oils,shortenings or fats which may be employed include those derived fromplant, animal, and marine sources, as well as edible fat substitutes,and mixtures thereof. Exemplary of vegetable oils which may be employedare palm oil, corn oil, safflower oil, soybean oil and cottonseed oil,which may be hydrogenated, and mixtures thereof.

In embodiments, fats, oils, or waxes may be used as a protective coatingon the encapsulant and to control the rate of release of theencapsulant. The oils or fats may be from animal and vegetable sources.The protective oils are stable against oxidation, unlike the readilyoxidizable encapsulated oils.

The oil-in-water emulsions according to the present invention mayoptionally include an emulsifier in effective emulsifying amounts to aidin the stabilization of the emulsion. Conventional emulsifiers used infood and pharmaceutical products, such as mono-glycerides anddi-glycerides, may be selected for use according to the presentinvention.

Reduction of Water Content of the Emulsion by Admixing with a MatrixMaterial

After homogenization, the water content of the emulsion is reduced sothat the film-forming component forms a film around the oil droplets andencapsulates the encapsulant. The water content of the emulsion may bereduced by admixing the emulsion with at least one plasticizable matrixmaterial to thereby encapsulate the film-coated oil droplets within thematrix material. The aqueous component, such as water, is adsorbed by orinteracts with the matrix material to thereby increase the concentrationof the film-forming component and to cause it to form a film andprecipitate around the oil droplets. Thus, if microcapsules of the oilcomponent and the film-forming component are obtained, the microcapsulesare further encapsulated by the matrix component. Preferably, the matrixmaterial comprises a plasticizable matrix material, such as flour fromwheat or durum, rye, corn, buckwheat, barley, oat or other grains, whichis plasticized by the aqueous component to thereby encapsulate thefilm-coated oil droplets within the plasticized matrix material.Admixing of the emulsion and the matrix material may be performed in acontinuous dough mixer or in an extruder to form a dough.

In preferred embodiments, all or substantially all of the plasticizermay be the water or aqueous liquid contained in the oil-in-wateremulsion encapsulant component and the mobilizing plasticizer used todissolve the acidic antioxidant. Additional, separately addedplasticizer for the matrix material, such as water, fruit juice or otheraqueous plasticizers may be added to the matrix material to assist inthe formation of a dough or to adjust its viscosity for formability. Theformable mixture or dough of the present invention may have a totalplasticizer content of from about 6% by weight up to about 80% byweight, preferably about 20% by weight to about 45% by weight of theproduct or dough of the present invention. When plasticizers areemployed at high levels, for example above about 80% by weight, a thinlow viscosity dough may result which cannot be cut immediately at theextrusion die. However, cutting the exiting dough ropes into individualpellets may be done by known mechanical means. Lower plasticizercontents, such as below about 5% may result in a dry product, whichwould be too fragile after forming and would fall apart. Low plasticizercontents, such as below about 5%, also makes a mixture or doughdifficult to extrude unless a fat is present. Low plasticizer contentsmay also generate frictional heating during extrusion forming and wouldbe detrimental to a heat sensitive encapsulant.

In embodiments of the invention, the total amount of water or themoisture content of the dough, from all sources including water in theemulsion, water in the antioxidant solution, and separately addedwater), may range up to about 80% by weight, for example up to about 35%by weight, based upon the weight of the dough.

In the method of admixing the oil-in-water encapsulant emulsioncomponent into a plasticizable matrix material of the present invention,droplet size is inversely proportional to stability. Accordingly,desirable droplet sizes in the formable mixture or dough of the presentinvention may range from about 0.5 microns to about 50 microns indiameter, preferably less than about 10 microns in diameter, morepreferably less than about 2 microns, most preferably less than about 1micron. As evidence of emulsion stability, the droplet diameters of theemulsion of the present invention remain substantially unchangedthroughout the admixture of the emulsion with a matrix material to forma dough or formable mixture.

According to the present invention, the plasticizable matrix material isplasticized by water or an aqueous liquid and also a non-aqueousplasticizer or softener such as glycerol or propylene glycol. Use of thenon-aqueous plasticizer or softener in forming the dough, reduces theamount of water needed for formability and therefor reduces the amountof drying needed for obtaining a shelf-stable water activity. Reducingthe amount of drying saves energy and also helps to reduce destructionof heat sensitive components. In embodiments of the invention, theamount of non-aqueous plasticizer or softener such as glycerol orpropylene glycol may range up to about 80% by weight, based upon thetotal amount of plasticizer in the dough or extrudate. After drying, theproportion of water is substantially reduced and the proportion of thenon-aqueous plasticizer is increased. For example, after drying, theamount of non-aqueous plasticizer or softener such as glycerol orpropylene glycol in the dried pellets may range up to about 100% byweight, based upon the total amount of aqueous and non-aqueousplasticizers in the dried product or pellet.

The preferred plasticizable matrix materials of the present inventionare high gluten content flours, gluten from wheat, durum wheat orsemolina, dairy proteins, such as sodium caseinate, potassium caseinate,or calcium caseinate, pregelatinized or modified starch, pentosans,hydrocolloids and mixtures thereof. For easier distribution ordispersibility in liquids such as water, finally ground or powderedcookies or crackers or ground cookie-like or cracker-like products maybe employed as a matrix material. Other plasticizable matrix materialsuseful in accordance with the present invention include biopolymers suchas carbohydrates, polymers such as polyvinylpyrrolidone, gums andvegetable or dairy proteins. Exemplary starches which may be used in thepresent invention are modified starches or pregelatinized starchesderived from corn, wheat, rice, potato, tapioca, or high amylose starch.Sources of starch which may be used also include flours from grains suchas corn, wheat, durum wheat, rice, barley, oat, or rye, and mixturesthereof. The most preferred plasticizable matrix materials according tothe present invention include durum wheat flour, wheat protein, heattreated wheat flour, semolina, gluten, a dairy protein such as sodiumcaseinate protein, modified starches and mixtures thereof, such as amixture of durum flour with sodium caseinate or with wheat proteinisolate (gluten).

In embodiments of the present invention, the matrix material componentmay be at least about 30% by weight, for example about 40% by weight toabout 95% by weight, preferably from about 45% by weight to about 75% byweight, based on the weight of the final product. The percentage ofprotein in the matrix material may range from about 5% by weight toabout 80% by weight protein, more preferably from about 10% by weight toabout 30% by weight. Increasing protein content in the matrix canimprove efficiency of encapsulation (i.e. reduce free surface oil).

Durum products or ingredients which may be used in the present inventioninclude durum semolina, durum granular, durum flour and mixturesthereof. Durum semolina is preferred. Durum semolina is the purified orisolated middlings of durum wheat prepared by grinding and boltingcleaned durum wheat to such fineness that when tested by the methodprescribed in 21 CFR §137.300(b)(2), it all passes through a No. 20 U.S.sieve, but not more than 3 percent passes through a No. 100 U.S. sieve.The semolina is freed from bran coat or bran coat and germ to such anextent that the percent of ash therein, calculated to a moisture-freebasis, is not more than 0.92 percent. The durum granular product is asemolina to which flour has been added so that about 7% passes throughthe No. 100 U.S. sieve. Durum flour has not less than 98 percent passingthrough the No. 70 U.S. sieve.

In embodiments of the invention, substantially non-plasticizable matrixcomponents may be used to facilitate processing and to increase the rateof release of encapsulants from the matrix. Such substantiallynon-plasticizable matrix materials may comprise substantiallynon-gelatinized starch in a preferred embodiment, as well ascarbohydrates which have a lower molecular weight than starches, bulkingagents, fiber or other, inert materials, such as cellulose, fiber orhemi-cellulose. Sources of starch which may be used include flours orstarches from grains such as corn, wheat, durum wheat, rice, barley,oat, or rye, and mixtures thereof. In embodiments of the invention, theamount of matrix component which is substantially non-plasticizable isat least about 10% by weight, preferably at least about 25% by weight,and can range up to about 98% by weight, based on the total weight ofthe at least one plasticizable matrix material and the matrix componentwhich is substantially non-plasticizable. For quickest release rates,the amount of substantially non-plasticizable matrix material, such asnon-gelatinized starch, may be at least about 60% by weight, and as lowas about 20% by weight, based upon the total weight of the matrixmaterials.

Additional rate release controlling agents may be added to the admixtureof the present invention, including components that may manage, controlor affect the flow, diffusion or distribution of water or aqueous-basedcompositions into and within the final product particles. The additionalingredient or component for controlling the rate of release of theencapsulant may be a hydrophobic agent such as polyethylene,polyurethane, polypropylene, polyvinylchloride, polyvinylacetate, a fat,oil, wax, fatty acid, or emulsifier which increases the hydrophobicityof the matrix. The increased hydrophobicity helps to prevent or delayspenetration of water or gastric juice into the matrix. Other ingredientswhich may be used to control the rate of the release are componentswhich have a high water binding capacity which delay or prevent a fastdissolving of the matrix and thereby delay the release of theencapsulant into the matrix. Exemplary of high water binding capacitycomponents which may be used are proteins, such as wheat gluten,gelatin, casein, and caseinates, such as sodium caseinate, hydrocolloidgums, and the like.

In embodiments of the invention, one or more flavors such as a fruitflavor or vanilla or vanillin or other taste modifying components, suchas cocoa powder or cinnamon powder may be added to the matrix materialto aid in masking off odors and off flavors. Exemplary amounts of thosecomponents or flavors which may be used may range up to about 20% byweight, for example up to about 5% by weight, based upon the weight ofthe matrix material.

In embodiments of the invention, titanium dioxide or zinc oxide may beadded to the matrix material to improve pellet shape and as a whitenerto lighten the color of the pellets. Exemplary amounts of whitener whichmay be used may range up to about 10% by weight, based upon the weightof the matrix material.

The admixing step of the present invention may be preferably carried outin an extruder to form an admixture of: 1) an oil-in-water encapsulantemulsion component, 2) a dry matrix material component which may includea plasticizable matrix material, an optional non-plasticizable matrixmaterial, an optional rate release controlling agent, and an optionalflavor 3) a solubilized acidic antioxidant solution or component whichmay include an acidic antioxidant, a mobilizing plasticizer or softenersuch as glycerol, and water, and 4) separately added water. Lowextrusion pressures and temperatures are employed to avoid coalescence,oil separation and extruder surging. Generally, low viscosities arerequired to extrude at low pressures. However, increasing the viscositytends to increase shear which can destroy an emulsion.

Low extrusion pressures help to prevent coalescence, prevent theseparation of an emulsion and prevent extruder surging. To achieve lowpressures, dough viscosity may be reduced by increasing the amount ofplasticizer, such as water. However, the dough viscosity should besufficiently high so as to allow for the attainment of a formable,cuttable mixture at the die. Desirable extruder pressures under whichthe formable mixture may be formed may range from about 14.5 psig toabout 2175 psig (about 100 kPa to about 14997 kPa), preferably fromabout 29 psig to about 1450 psig (about 200 kPa to about 9998 kPa), morepreferably from about 72.5 psig to about 725 psig (about 500 kPa toabout 4999 kPa). In embodiments of the invention, die operatingpressures may range from about 70 psig to about 800 psig (about 483 kPato about 5516 kPa), generally from about 100 psig to about 300 psig(about 690 kPa to about 2069 kPa).

In making the formable mixture or dough of the present invention, it ispreferable in the admixing method of the present invention to achieve abalance between shear, which reduces particle size on the one hand, andlower viscosity, which reduces shear on the other hand. Reducing dropletsize reduces coalescence and ensures protection of each individualencapsulant droplet within the particles according to the presentinvention.

In embodiments of the present invention, the pre-emulsified components,followed by the plasticizer/acidic antioxidant solution, and then byoptionally added water may be injected into the upstream end of theextruder to achieve plasticization of the plasticizable matrix materialwithout substantial coalescence, or oil separation or surging even athigh oil contents. Mixing is continued towards the extruder die whileoptionally adjusting the product temperature for sufficient formability.The plasticizable matrix material is plasticized by the water or aqueousliquid, and the mobilizing plasticizer of the plasticizer/acidicantioxidant solution. The optional substantially non-plasticizablematrix component is not plasticized by the liquid plasticizers generallyat a temperature of less than about 60° C., preferably less than 50° C.,most preferably less than about 45° C., for example at room temperature,or down to about 0° C. Removal of liquid plasticizer prior to extrusionis not needed to adjust the viscosity of the mixture for formability. Inembodiments of the invention, the extruder barrel temperatures may bemaintained in a range of about −5° C. to about 25° C., preferably fromabout 5° C. to about 10° C. Generally, die operating temperatures mayrange from about 10° C. to about 50° C., for example from about 15° C.to about 30° C.

A formable mixture may be obtained without substantially gelatinizing orcooking the plasticizable matrix material or the optional substantiallynon-plasticizable matrix component. The plasticizable matrix material inthe formable mixture may become glassy upon drying, even though it wasnot cooked or substantially gelatinized during plasticization to obtainthe formable mixture. However, use of the non-aqueous mobilizingplasticizer or softener, such as glycerol, may desirably provide anon-brittle, softer or rubbery texture which is less prone to cracking,oil leakage, and ambient oxygen penetration.

The amount of the active component or encapsulant which may beencapsulated or embedded into the matrix may be from about 1% by weightto about 85% by weight, preferably from about 3% by weight to about 50%by weight, and most preferably from about 5% by weight to about 40% byweight, for example from about 5% by weight to about 30% by weight,based on the total weight of the plasticizable matrix material of theformable mixture or dough of the present invention or based on the totalweight of the pellet.

The admixture or dough may be extruded through extrusion dies and cut orotherwise formed into pieces or pellets with no or substantially noexpansion of the extrudate.

In embodiments of the invention, the dough may be extruded throughcircular die holes having a diameter ranging from 0.1 mm to 5 mm(preferably 0.25 mm to 2 mm, most preferably 0.5 mm to 1 mm) and facecut to 0.1 mm to 5 mm (preferably 0.25 mm to 2 mm, most preferably 0.5mm to 1 mm). For example, pellet dimensions of ˜0.5 mm (diameter)×0.5 mm(length) may be produced. The dough may be kept cold during extrusion,for example less than approximately 30° C.

A flow agent such as starch may be added at the cutter apparatus tomaintain the discrete nature of the particles or pellets and to assistthe air conveying of pellets as they may stick to one another at highextrusion moisture contents or with high matrix protein levels.

The matrix can be composed of one or several different ingredients,ranging from durum wheat flour, sodium or potassium caseinate, wheyprotein isolate, wheat protein (or protein from other animal orvegetable sources), heat-treated flour, such as heat-treated wheatflour, starch, alginate, to other hydrocolloids, etc. that may provideadded oxidation protection.

In embodiments of the invention, the freshly extruded pellets cancontain an oil load between about 1 to about 85% by weight, for exampleabout 1% to about 35% by weight, (preferably about 5 to about 30% byweight, most preferably about 10% to about 25% by weight), at moisturecontents between approximately 15% to 80% by weight, for exampleapproximately between 15% to about 35% by weight, based on the totalweight of the pellet.

The extrudate or pieces may then be surface dried using conventionaldrying equipment, such as a rotary dryer. The pellets can be conveyed toa long (˜2 ft ID×4 ft. long) rotating enrober with air blowingcountercurrent to extrudate or pellet flow. Dehumidified air ispreferred for more efficient drying. Hot air (dehumidified or ambient)up to approximately 280° C. can be used to surface dry the pellets.Generally, the air drying temperature may be from about 37° C. to about82° C., but more preferred is an air temperature of about 50° C. toabout 60° C. Surface drying facilitates optional subsequent coating.Even at elevated hot air temperatures, the product temperature at theexit of the enrober can still remain below approximately 100° F. (˜37.7°C.). In embodiments of the invention, up to about 10% by weight moistureor more, for example up to about 20% by weight, may be removed from thepellets during surface drying in the rotary dryer. Other conventionaldrying apparatus, such as fluid bed drying or static bed drying may alsobe employed.

In embodiments of the invention, the surface dried extrudate or pelletsor pieces may optionally be coated or surface treated with a protectivefilm or coating to either prevent early release or to enable controlledrelease of the encapsulant from the pellets or pieces. Surface dryingafter extrusion and before coating facilitates application of aprotective coating solution. For instance, drier pellets can accepthigher levels of coating before clumping or agglomeration could becomean issue. The protective coating may be hydrophilic or oleophobic so asto inhibit outward migration of the oil component to the surface of thepellet where it would be subject to oxidation. Exemplary film-buildingsubstances or protective coatings which may be employed are a proteinstemming from whey, corn, wheat, soy, or other vegetable or animalsources, such as aquazein (an aqueous corn protein solution), anddenatured whey protein isolate solution (with or without a plasticizersuch as sucrose or glycerol) a fat, such as melted chocolate fat,shellac, wax, film-forming starch solutions, alginates, other non-starchpolysaccharides, an enteric coating, and mixtures thereof.

Denatured whey protein isolate films plasticized with sucrose arepreferred for its function as an oxygen barrier. Other biopolymers thatmay be used in lieu of or in addition to denatured whey protein are soyprotein isolate, modified food starch,hydroxymethylpropylmethylcellulose, and shellac. Exemplary polymer andplasticizer ratios which may be employed range from about 1:0.25 toabout 1:3 parts by weight of polymer to plasticizer. For example, acoating or film composition for application to the surface dried pelletsmay be produced by heating a solution consisting of deionized water andwhey protein to about 90° C. and holding at that temperature for about30 minutes to denature the protein. The solution may then be cooled andthe plasticizer, such as sucrose, may be added at a ratio of 1 part byweight protein to 3 parts sucrose. The formula of the coating solutionmay be 5% by weight denatured whey protein, 15% by weight sucrose, and85% by weight de-ionized water.

The film-building substance or protective coating may also contain aflavoring material, and additional components that delay or prevent theaccess of light, oxygen, and/or water to the matrix. Light barriers suchas titanium dioxide, carbon black, edible ink, cocoa, or the like may beemployed.

In embodiments of the invention, the coating solution may be applied asa fine mist, atomized by nitrogen and sprayed onto the surface of thepellets in a rotating enrober. Multiple coatings can be applied withintermediate drying in-between coatings. The coating material mayconstitute from about 1% by weight to about 20% by weight of the finalproduct mass.

Application of the optional protective coating may also be achieved bypan coating the pieces or pellets immediately after extrusion and priorto final drying. Multiple pan coatings can be applied with intermediatedrying in-between coating layers. Fluid bed coating, coating with arotating enrober drum can also be an option for coating the pieces orpellets, though pan coating may prove more efficient and cost effective.

In an alternate, optional coating method, the surface dried pieces orpellets may be coated with a protective film or coating, such as afunctional protein coating, to produce clusters or to produce cerealparticulates in a single step. Similarly, the pellets may be added intoa confectionery or fat-based coating, preferably a low moistureconfectionery or fat-based coating. The coating solution may be used tobind pellets to each other to form a pellet cluster, or to bind pelletsto an already produced cereal particulate, such as a cereal cluster,while coating the pellets in the process. The particulate may then beused as the delivery mechanism in a cereal product. The cluster may alsocamouflage the pellet, masking its appearance.

The uncoated pellets, coated pellets or cluster particulates, may bedried to their final moisture content in conventional drying equipmentsuch as a static bed tray dryer, a continuous conventional dryer, or afluid bed (continuous or batch) dryer. Convective drying by air, whichmay be dehumidified or ambient, nitrogen, or carbon dioxide, may beemployed. Exemplary final moisture contents may range from about 2% byweight to about 10% moisture by weight, based upon the weight of thedried pellets, clusters, or particulates. The drying temperature mayrange from ambient to 100° C., or more preferably ambient to about 65°C. The pellets, clusters, or particulates may be dried to achieve shelfstable water activity of less than or equal to about 0.7 and a storagestability or shelf life of at least about six months, preferably atleast about twelve months, most preferably at least about thirty-sixmonths. In embodiments of the invention the shelf stable water activitymay be less than or equal to about 0.9 in a moist product where anoptional antimycotic or antimicrobial agent may be employed.

In embodiments of the invention, the encapsulated component such as fishoil or flax oil, or oil from algae, may contain up to about 90% byweight readily oxidizable components, for example up to about 45% byweight, preferably from about 1% by weight to about 40% by weight, morepreferably from about 10% by weight to about 30% by weight oil or otherreadily oxidizable components, such as polyunsaturated fatty acids.

The products of the present invention may possess either a chewy,rubbery, non-brittle, or non-glassy texture or a crispy texture. Theproducts of the present invention may be in the form of discreteparticles, pellets, clusters, or tablets. They may be spherical inshape, curvilinear or lens-shaped, flat discs, oval shaped, or the like.In embodiments of the invention, the diameter of the particles may rangeup to about 7 mm, for example from about 0.3 mm to about 7 mm and thelength-to-diameter ratio (1/d) ratio may be from about 0.1 to about 10,for example about 0.5 to about 2, preferably about 1. In someembodiments of the invention, the diameter of the particles may be fromabout 0.15 mm to about 4 mm, preferably from about 0.20 mm to about 1.0mm or about 200 microns to about 1000 microns. The particles aregenerally uniform in size, may be chewy or partially glassy, andgranular to increase palatability to humans and animals in asubstantially compact form that is easy to swallow with or withoutchewing. The products of the invention are non-expanded, generally notleavened, and may exhibit a non-puffed, substantially non-cellularstructure. The starch component of the matrices may be substantiallyungelatinized or partially gelatinized, and not substantiallydestructurized or dextrinized. Exemplary specific densities of theproducts of the present invention are between about 800 g/liter andabout 1500 g/liter (about 0.8 to about 1.5 g/cm³).

The encapsulated products of the present invention may be incorporatedwith or without grinding into foods intended for human or animalconsumption such as baked goods, for example, bread, wafers, cookies,crackers, pretzels, pizza, and rolls, ready-to-eat breakfast cereals,hot cereals, pasta products, snacks such as fruit snacks, salty snacks,grain-based snacks, and microwave popcorn, dairy products such asyoghurt, cheese, and ice cream, sweet goods such as hard candy, softcandy, and chocolate, beverages, animal feed, pet foods such as dog foodand cat food, aqua-culture foods such as fish food and shrimp feed, andspecial purpose foods such as baby food, infant formulas, hospital food,medical food, sports food, performance food or nutritional bars, dietarysupplements, or fortified foods, food preblends or mixes for home orfood service use, such as preblends for soups or gravy, dessert mixes,dinner mixes, baking mixes such as bread mixes, and cake mixes, andbaking flour.

In preferred embodiments, the active encapsulant is a fish oil or algaeoil containing omega-3 fatty acids, or a flax oil. The encapsulatedproduct may be redispersed as a liquid, or as a solid for human food,animal feed, or pharmaceutical purposes. The products of the presentinvention may be used as or incorporated into foods for specialpurposes, such as performance foods, mood foods, medical foods,nutritional snacks or supplements, sport foods such as power bars, babyfoods, toddler foods, infant foods, or foods for pharmaceutical purposesor other dietetic purposes. The discrete particulates or granules of thepresent invention may be used as a topping for breakfast cereals,snacks, soups, salad, cakes, cookies, crackers, puddings, desserts orice cream. They may also be used as a granular ingredient for yogurts,desserts, puddings, custards, ice cream or other pasty or creamy foods.Regularly sized pieces may be individually packaged or used asnutritional snacks or, for example added to or formed into nutritionalfood in bar form.

The present invention is further illustrated by the followingnon-limiting examples where all parts, percentages, proportions, andratios are by weight, and all temperatures are in ° C. unless otherwiseindicated:

Example 1

The ingredients and their relative amounts which may be used toencapsulate a fish oil using a sodium caseinate emulsion and anerythorbic acid antioxidant solution are:

Dry Matrix Material Component Ingredient Amount, grams Weight %Volatiles (moisture) (wt %) Durum Flour 128 80 10 Wheat protein 32 20 10TOTAL 160 100

The dry feed or dry matrix material component may be prepared byblending the durum flour and the wheat protein to obtain a substantiallyhomogeneous dry blend. The composition of the dry matrix materialcomponent may be about 72% by weight durum flour, about 18% by weightwheat protein, and about 10% by weight water.

Emulsion, Aqueous Phase Volatiles (moisture) Ingredient Amount, gramsWeight % (wt %) Deionized Water 6030 90 100 Sodium Caseinate 670 10 5TOTAL 6700 100

The water and sodium caseinate may be admixed to form an aqueoussolution. The aqueous solution may then be hydrated overnight underrefrigerated conditions at about 40° F.

Emulsion, Oil Phase Volatiles (moisture) Ingredient Amount, grams Weight% (wt %) Fish Oil, Marinol C-38 3510.3 97.3 0 Vanilla Flavor 97.4 2.7 1TOTAL 3607.7 100.0

In order to make an emulsion, the fish oil and vanilla flavor may bepreblended and added to the aqueous solution under a nitrogen blanketand using a high shear mixer such as a ULTRA-TURRAX ROTOSOLVER mixed athigh shear for about 5 minutes. The resulting emulsion may have acomposition of about 58.8 wt. % water, 34.1 wt % fish oil, 6.2 wt. %sodium caseinate, 0.9 wt. % vanilla.

The emulsion may be homogenized in an APV multistage homogenizer havinga total stage pressure of approximately 5801 psi (400 bar) for twodiscrete passes. During homogenization, a nitrogen blanket may be kepton all emulsion containers.

Plasticizer/Acidic Antioxidant Solution Volatiles (moisture) IngredientAmount, grams Weight % (wt %) Glycerol 3749.9 74.7 0.0 Erythorbic Acid768.1 15.3 1.5 Deionized Water 502.0 10.0 100.0 TOTAL 5020.0 100.0

The acidic antioxidant erythorbic acid may be dissolved in a mixture ofthe glycerol mobilizing plasticizer and deionized water to obtain aplasticizer/acidic antioxidant solution using conventional mixingequipment.

The dry matrix material component, homogenized emulsion, erythorbic acidsolution, and additional water for dough viscosity adjustment may becombined in an extruder to obtain a formable dough. The extruder may bea seven barrel Buhler 44 twin screw extruder comprising a die plate witheight die inserts, each insert having 162 holes where the holes have aninner diameter of 0.5 mm. The extruder feed opening may be blanketedwith nitrogen gas to avoid oxidation.

The dry matrix feed to the extruder functions as an encapsulating matrixfor the emulsion and thus form a dough. The dry feed may be fed to thefirst barrel at a rate of about 160 g/min. The homogenized emulsion maythen serve as a liquid feed to the second barrel of the extruder at anemulsion feed rate of about 114 g/min. The dry feed or matrix materialsare admixed and conveyed in the extruder to plasticize the matrixmaterials and obtain a mass having about 42% by weight durum flour,about 10.5% by weight wheat protein, about 30.3% by weight water, about2.6% by weight sodium caseinate, about 14.2% by weight oil, and about0.4% by weight flavor.

Next, the plasticizer/acid solution may be fed to the third barrel ofthe extruder at a feed rate of about 52 g/m to give a composition havingabout 35.3% by weight durum flour, about 8.8% by weight wheat protein,about 27.1% by weight water, about 2.2% by weight sodium caseinate,about 11.9% by weight oil, about 0.3% by weight flavor, about 11.9% byweight glycerol, and about 2.4% by weight erythorbic acid.

The additional water may then be added in the third barrel at a rate ofabout 7.0 g/min and the ingredients may be mixed and conveyed to obtainan extrudable dough having about 34.6% by weight durum flour, about 8.6%by weight wheat protein, about 28.6% by weight water, about 2.1% byweight sodium caseinate, about 11.7% by weight oil, about 0.3% by weightflavor, about 11.7% by weight glycerol, and about 2.4% by weighterythorbic acid.

The dough may be extruded at a screw speed of approximately 80 rpm toform 0.5 mm long pellets. The pellets may comprise approximately 34.6%by weight durum flour, about 8.6% by weight wheat protein, about 28.6%by weight water, about 2.1% by weight sodium caseinate, about 11.7% byweight oil, about 0.3% by weight flavor, about 11.7% by weight glycerol,and about 2.4% by weight erythorbic acid.

The pellets may then be surface dried in a long (2 ft.×4 ft.) rotatingenrober and subjected to final drying in a fluid bed dryer to evaporateabout 74.7 g/min of moisture, and produce about 258.3 g/min of drypellets. The dry pellets may contain about 44.6% by weight durum flour,about 11.2% by weight wheat protein, about 8.0% by weight water, about2.7% by weight sodium caseinate, about 15.0% by weight oil, about 0.4%by weight flavor, about 15.0% by weight glycerol, and about 3.0% byweight erythorbic acid.

Examples 2-11

The ingredients and their relative amounts which may be used toencapsulate a fish oil using a sodium caseinate emulsion and anerythorbic acid or ascorbic acid antioxidant solution are:

Examples 2-11

Examples, Weight % Ingredients (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)Durum Flour 52.7 51.5 50.3 52.7 51.5 50.3 49.1 47.9 51.5 49.1 WheatProtein A 13.2 12.9 12.6 13.2 12.9 12.6 12.3 12.0 — — Wheat Protein B¹ —— — — — — — — 12.9 12.3 Glycerol 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.015.0 15.0 Erythorbic Acid 1.5 3.0 4.5 — — — — — — — Ascorbic Acid — — —1.5 3.0 4.5 6.0 7.5 3.0 6.0 Na-Caseinate 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.22.2 2.2 Vanilla Flavor 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Fish Oil,Marinol 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 C38 Kosher²Total Dry Matter 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0100.0 ¹Wheat Protein, 3.1% Lactic Acid, 130 ppm Sulfite ²Addition of 200ppm TBHQ based on oil content

Dry Matrix Material Component Volatiles (moisture) Ingredient Amount,grams Weight % (wt %) Durum Flour 12800 80 10 Wheat Protein 3200 20 10TOTAL 16000 100

The dry feed or dry matrix material component may be prepared byblending the durum flour and the wheat protein to obtain a substantiallyhomogeneous dry blend. The composition of the dry matrix materialcomponent may be about 72% by weight durum flour, about 18% by weightwheat protein, and about 10% by weight water.

Emulsion, Aqueous Phase Volatiles (moisture) Ingredient Amount, gramsWeight % (wt %) Deionized Water 6030 90 100 Sodium Caseinate 670 10 5TOTAL 6700 100

The water and sodium caseinate may be admixed to form an aqueoussolution. The aqueous solution may then be hydrated overnight underrefrigerated conditions at about 40° F.

Emulsion, Oil Phase Volatiles (moisture) Ingredient Amount, grams Weight% (wt %) Fish Oil, Marinol 3510 97.5 0 C-38 Kosher Vanilla Flavor 90 2.51 TOTAL 3600 100

In order to make an emulsion, the fish oil and vanilla flavor may bepre-blended and added to the aqueous solution under a nitrogen blanketand using a high shear mixer such as a ULTRA-TURRAX ROTOSOLVER mixed athigh shear for about 5 minutes. The resulting emulsion may have acomposition of about 54.3 wt. % water, 39.0 wt % fish oil, 5.7 wt. %sodium caseinate, 0.9 wt. % vanilla.

The emulsion may be homogenized in a Microfluidics Microfluidizer havinga total operating pressure of approximately 10,000 psi (689.5 bar) forone discrete pass. During homogenization, a nitrogen blanket may be kepton all emulsion containers.

Plasticizer/Acidic Antioxidant Solutions Ingredients (grams) (2) (3) (4)(5) (6) (7) (8) (9) (10) (11) Glycerol 4000 4000 4000 4000 4000 40004000 4000 4000 4000 Erythorbic Acid 400 800 1200 Ascorbic Acid 400 8001200 1600 2000 800 1600 Water 1000 1000 1000 1000 1000 1000 1000 10001000 1000 Total 5400 5800 6200 5400 5800 6200 6600 7000 5800 6600

The acidic antioxidant may be dissolved in a mixture of the glycerolmobilizing plasticizer and deionized water to obtain aplasticizer/acidic antioxidant solution using conventional mixingequipment while heating the solution to 60 to 80° C. and holding thesolution at this temperature until all the acid crystals aresufficiently dissolved.

The dry matrix material component, homogenized emulsion,plasticizer/acid solution, and additional water for dough viscosityadjustment may be combined in an extruder to obtain a formable dough.The extruder may be a seven barrel Buhler 44 twin screw extrudercomprising a die plate with eight die inserts, each insert having 162holes where the holes have an inner diameter of 0.5 mm. The extruderfeed opening may be blanketed with nitrogen gas to avoid oxidation.

The dry feed to the extruder functions as an encapsulating matrix forthe emulsion and thus form a dough. The dry feed may be fed to the firstbarrel. The homogenized emulsion may then serve as a liquid feed to thesecond barrel. Next, the plasticizer/acid solution may be fed to thethird barrel and additional water may then be added in the third barrel.The liquid components may be admixed and conveyed in the extruder toplasticize the matrix materials. The dough may be extruded at a screwspeed of approximately 80 rpm to form 0.5 mm long pellets. The relativeinput stream flow rates into the extruder may be:

Extruder Feed Rates Input Streams (g/min) (2) (3) (4) (5) (6) (7) (8)(9) (10) (11) Dry Matrix 160.5 156.9 153.2 160.5 156.9 153.2 149.6 145.9156.9 149.6 Component Emulsion 83.7 83.7 83.7 83.7 83.7 83.7 83.7 83.783.7 83.7 Erythorbic Acid/ 44.0 47.3 50.6 Glycerol Solution AscorbicAcid/ 44.0 47.3 50.6 53.8 57.1 47.3 53.8 Glycerol Solution AdditionalWater 11.8 12.2 12.5 11.8 12.2 12.5 12.9 13.3 12.2 12.9 Total Mass Flow300 300 300 300 300 300 300 300 300 300

The pellets may then be dried in a fluid bed dryer at 60° C. andeffectively dried to moisture content below 9% moisture.

Examples 12-13

The ingredients and their relative amounts which may be used toencapsulate a fish oil using a sodium caseinate emulsion and an ascorbicacid antioxidant solution are:

Examples, Weight % Ingredients (12) (13) Durum Flour 46.5 42.5 WheatProtein A — — Wheat Protein B¹ 11.6 10.6 Glycerol 15.0 15.0 ErythorbicAcid — — Ascorbic Acid 10.0 15.0 Na-Caseinate 1.5 1.5 Vanilla Flavor 0.40.4 Fish Oil, Marinol C38 15.0 15.0 Kosher² Total Dry Matter 100.0 100.0¹Wheat Protein, 3.1% Lactic Acid, 130 ppm Sulfite ²Addition of 200 ppmTBHQ based on oil content

Dry Matrix Material Component Ingredient (grams) (12) (13) Volatiles(moisture) (wt %) Durum Flour 3769 3474 10 Wheat Protein 942 869 10Ascorbic Acid 289 657 TOTAL 5000 5000

The dry feed or dry matrix material component may be prepared byblending the durum flour and the wheat protein and ascorbic acid toobtain a substantially homogeneous dry blend.

Emulsion, Aqueous Phase Volatiles (moisture) Ingredient Amount, gramsWeight % (wt %) Deionized Water 6030 90 100 Sodium Caseinate 670 10 5TOTAL 6700 100

The water and sodium caseinate may be admixed to form an aqueoussolution. The aqueous solution may then be hydrated overnight underrefrigerated conditions at about 40° F.

Emulsion, Oil Phase Volatiles Ingredient Amount, grams Weight %(moisture) (wt %) Fish Oil, Marinol 3510 97.5 0 C-38 Kosher VanillaFlavor 90 2.5 1 TOTAL 3600 100

In order to make an emulsion, the fish oil and vanilla flavor may bepre-blended and added to the aqueous solution under a nitrogen blanketand using a high shear mixer such as a ULTRA-TURRAX ROTOSOLVER mixed athigh shear for about 5 minutes. The resulting emulsion may have acomposition of about 45.3 wt. % water, 48.8 wt % fish oil, 4.7 wt. %sodium caseinate, 1.2 wt. % vanilla.

The emulsion may be homogenized in a Microfluidics Microfluidizer havinga total operating pressure of approximately 10,000 psi (689.5 bar) forone discrete pass. During homogenization, a nitrogen blanket may be kepton all emulsion containers.

Plasticizer/Acidic Antioxidant Solutions Ingredients (grams) (12) (13)Glycerol 4000 4000 Ascorbic Acid 1600 1600 Water 1000 1000 Total 54005800

The acidic antioxidant may be dissolved in a mixture of the glycerolmobilizing plasticizer and deionized water to obtain aplasticizer/acidic antioxidant solution using conventional mixingequipment while heating the solution to 60 to 80° C. and holding thesolution at this temperature until all the acid crystals aresufficiently dissolved.

The dry matrix material component, homogenized emulsion,plasticizer/acid solution, and additional water for dough viscosityadjustment may be combined in an extruder to obtain a formable dough.The extruder may be a seven barrel Buhler 44 twin screw extrudercomprising a die plate with eight die inserts, each insert having 162holes where the holes have an inner diameter of 0.5 mm. The extruderfeed opening may be blanketed with nitrogen gas to avoid oxidation.

The dry feed to the extruder functions as an encapsulating matrix forthe emulsion and thus form a dough. The dry feed may be fed to the firstbarrel. The homogenized emulsion may then serve as a liquid feed to thesecond barrel. Next, the plasticizer/acid solution may be fed to thethird barrel and additional water may then be added in the third barrel.The liquid components may be admixed and conveyed in the extruder toplasticize the matrix materials. The dough may be extruded at a screwspeed of approximately 80 rpm to form 0.5 mm long pellets. The relativeinput stream flow rates into the extruder may be:

Extruder Feed Rates Input Streams (g/min) (12) (13) Dry Matrix 165.9164.4 Component Emulsion 73.8 73.8 Ascorbic Acid/ 59.4 59.4 GlycerolSolution Additional .9 2.3 Water Total Mass Flow 300 300

The pellets may then be dried in a fluid-bed dryer at 60° C. andeffectively dried to a moisture content below 9% moisture.

The pellets of Examples (2)-(13) were tested to determined the oxidativestability using an Oxipres® apparatus commercially available fromMikrolab Aarhus A/S (Denmark).

The pellets were placed in the Oxipres® apparatus at a temperature of90° C. and a pressure of 5 bar. The induction period (the time at whichthe oxygen concentration began to be significantly consumed and thepressure started to decrease) was measured to determine the relativeoxidative stability of the pellets:

Example Induction Period, hours (2) 9.55 (3) 11.57 (4) 14.70 (5) 9.71(6) 12.96 (7) 14.63 (8) 17.19 (9) 22.03 (10) 14.39 (11) 27.37 (12)greater than 50 hours (13) greater than 50 hours

1. A method for encapsulating a readily oxidizable component comprising:a) forming an oil-in-water emulsion comprising a readily oxidizablecomponent and a film-forming component comprising a protein, b) admixingsaid oil-in-water emulsion with at least one matrix material, a liquidplasticizer for plasticizing said matrix material, and an acidicantioxidant for preventing oxidation of said readily oxidizablecomponent, said admixing being such so as to obtain a formable mixturewherein said at least one matrix material contains said acidicantioxidant and encapsulates oil droplets of said oil-in water emulsion,wherein said film forming component surrounds said oil droplets, andsaid matrix material and said acid antioxidant surround the film-coatedoil droplets c) forming said formable mixture into pieces, and d) dryingsaid pieces to obtain dried pieces, said plasticizer providing mobilityfor said acidic antioxidant in the dried pieces.
 2. A method accordingto claim 1 wherein said oil-in-water emulsion comprises at least one oilselected from the group consisting of fish oil, flax seed oil, oilderived from algae, and oils derived from a vegetable oil, animal oil,or microorganism which contains a substantial amount of a readilyoxidizable component.
 3. A method according to claim 1 wherein saidreadily oxidizable component comprises at least one polyunsaturatedfatty acid.
 4. A method according to claim 1 wherein said plasticizercomprises at least one polyol.
 5. A method according to claim 4 whereinsaid polyol is at least one member selected from the group consisting ofglycerol, propylene glycol, and sorbitol.
 6. A method according to claim1 wherein said acidic antioxidant comprises at least one member selectedfrom the group consisting of citric acid, ascorbic acid, and erythorbicacid.
 7. A method according to claim 1 wherein the amount of said acidicantioxidant is up to about 18% by weight, based upon the weight of thedried pieces.
 8. A method according to claim 1 wherein the amount ofsaid acidic antioxidant is from about 0.5% by weight to about 6% byweight, based upon the weight of the dried pieces.
 9. A method accordingto claim 1 wherein said film-forming component comprises a caseinate.10. A method according to claim 9 wherein said acidic antioxidantcomprises at least one member selected from the group consisting ofcitric acid, ascorbic acid, and erythorbic acid.
 11. A method accordingto claim 10 wherein said plasticizer comprises at least one memberselected from the group consisting of glycerol, propylene glycol, andsorbitol.
 12. A method according to claim 11 wherein said matrixmaterial comprises at least one member selected from the groupconsisting of durum wheat flour, a heat-treated flour, and proteinderived from wheat.
 13. A method according to claim 1 wherein saidacidic antioxidant is admixed with said liquid plasticizer to obtain asubstantially homogeneous antioxidant solution, and said antioxidantsolution is admixed with said matrix material to at least substantiallyplasticize said matrix material and to substantially uniformlydistribute said antioxidant throughout said matrix material.
 14. Amethod according to claim 13 wherein said emulsion is admixed with saidmatrix material to plasticize said at least one plasticizable matrixmaterial prior to admixing said antioxidant solution with said matrixmaterial.
 15. A method according to claim 14 wherein in said pieces,said oil-in-water emulsion comprises oil droplets comprising at leastone polyunsaturated fatty acid, at least substantially all of the oildroplets have a diameter of less than about 2 microns.
 16. A method asclaimed in claim 15 wherein said oil-in-water emulsion is homogenized ina homogenizer to obtain oil droplets wherein at least substantially allof the oil droplets have a diameter of less than about 2 microns.
 17. Amethod as claimed in claim 16 wherein said emulsion, said antioxidantsolution, and said matrix material are admixed in an extruder.
 18. Amethod for encapsulating an oil comprising a polyunsaturated fatty acidcomprising: a) forming an oil-in-water emulsion comprising at least onepolyunsaturated fatty acid and a film-forming component comprising aprotein, b) admixing said oil-in-water emulsion with at least one matrixmaterial, a liquid plasticizer for plasticizing said matrix material,and an acidic antioxidant for preventing oxidation of said at least onepolyunsaturated fatty acid, said admixing being such so as to obtain aformable mixture wherein said at least one matrix material contains saidacidic antioxidant and encapsulates oil droplets of said oil-in wateremulsion, wherein said film forming component surrounds said oildroplets, and said matrix material and said acid antioxidant surroundthe film-coated oil droplets c) forming said formable mixture intopieces, and d) drying said pieces to obtain dried pieces, saidplasticizer providing mobility for said acidic antioxidant in the driedpieces.
 19. A method as claimed in claim 18 wherein said emulsionincludes an antioxidant.
 20. A method for encapsulating a readilyoxidizable component, comprising: a) forming an oil-in-water emulsioncomprising a readily oxidizable component and a film-forming componentcomprising a protein, b) admixing said oil-in-water emulsion with atleast one matrix material, a liquid plasticizer for plasticizing saidmatrix material, and an acidic antioxidant for preventing oxidation ofsaid readily oxidizable component, thereby obtaining a formable mixturewherein said at least one matrix material contains said acidicantioxidant and encapsulates oil droplets of said oil-in water emulsion,wherein said film forming component surrounds said oil droplets, andsaid matrix material and said acid antioxidant surround the film-coatedoil droplets c) forming said formable mixture into pieces, and d) dryingsaid pieces to obtain dried pieces, wherein the amount of said acidicantioxidant is from about 1% by weight to about 40% by weight, basedupon the weight of the dried pieces.
 21. A method according to claim 20wherein said oil-in-water emulsion comprises at least one oil selectedfrom the group consisting of fish oil, seed oil, flax seed oil, oilderived from algae, and oils derived from a vegetable oil, animal oil,or microorganism which contains a substantial amount of a readilyoxidizable component.
 22. A method according to claim 20 wherein saidreadily oxidizable component comprises at least one polyunsaturatedfatty acid.
 23. A method according to claim 20 wherein said plasticizercomprises glycerol.
 24. A method according to claim 20 wherein saidacidic antioxidant comprises ascorbic acid or erythorbic acid, saltsthereof, isomers thereof, or derivatives thereof.
 25. A method accordingto claim 20 wherein the amount of said acidic antioxidant is from about2% by weight to about 30% by weight, based upon the weight of the driedpieces.
 26. A method according to claim 20 wherein the amount of saidacidic antioxidant is from about 3% by weight to about 20% by weight,based upon the weight of the dried pieces.
 27. A method according toclaim 20 wherein the amount of said oil in said dried pieces is fromabout 1% by weight to about 85% by weight, based upon the weight of thedried pieces.
 28. A method according to claim 20 wherein the driedpieces have a pH of about 2.5 to about
 8. 29. A method according toclaim 20, further comprising admixing up to about 10% by weight oftitanium dioxide or zinc oxide to the at least one matrix material,based upon the weight of the at least one matrix material.
 30. A methodaccording to claim 20, further comprising replacing up to about 100% byweight of the water in the oil-in-water emulsion with glycerol, basedupon the weight of the oil-in-water emulsion.
 31. A method forencapsulating a readily oxidizable component, comprising: a) forming anoil-in-water emulsion comprising a readily oxidizable component, afilm-forming component comprising a protein, and an acidic antioxidantby adding the protein to an acidified medium having a pH above or belowthe isoelectric point of the protein, for preventing the oxidation ofsaid readily oxidizable component b) admixing said oil-in-water emulsionwith at least one matrix material, thereby obtaining a formable mixturewherein said at least one matrix material encapsulates oil droplets ofsaid oil-in water emulsion, and wherein said film-forming componentsurround said oil droplets, and said matrix material surrounds thefilm-coated oil droplets c) forming said formable mixture into pieces,and d) drying said pieces to obtain dried pieces.
 32. A method accordingto claim 31 wherein the amount of said acidic antioxidant is from about1% by weight to about 40% by weight, based upon the weight of the driedpieces.
 33. A method for encapsulating an oil comprising apolyunsaturated fatty acid comprising: a) forming an oil-in-wateremulsion comprising at least one polyunsaturated fatty acid and afilm-forming component comprising a carbohydrate, a hydrocolloid, or astarch, b) admixing said oil-in-water emulsion with at least one matrixmaterial, a liquid plasticizer for plasticizing said matrix material,and an acidic antioxidant for preventing oxidation of said at least onepolyunsaturated fatty acid, thereby obtaining a formable mixture whereinsaid at least one matrix material contains said acidic antioxidant andencapsulates oil droplets of said oil-in water emulsion, wherein saidfilm forming component surrounds said oil droplets, and said matrixmaterial and said acid antioxidant surround the film-coated oil dropletsc) forming said formable mixture into pieces, and d) drying said piecesto obtain dried pieces.
 34. A method according to claim 33 wherein theamount of said acidic antioxidant is from about 1% by weight to about40% by weight, based upon the weight of the dried pieces.
 35. A methodaccording to claim 33, wherein the film-forming component is selectedfrom the group consisting of alginates, carrageenans, gums, modifiedstarch, and starch derivatives.